Insulated tank car



July 14, 1942. C. H. FOLMSBEE 2,290,038

INSULATED TANK CAR I Filed June 14, 1940 INVENTOR (7y; H fiimskq LNATTORN EY Patented July 14, 1942.

' INSULATED TANK CAB Clyde H. Folmsbee,

Ber-wick, la., assignor to American Car and Foundry Company, New

York, N. 2., a com.

tion of New Jersey Application June 14,1940. Serial No. 340,453

8 Claims.

This invention relates to tank cars in general,

and in particular to insulated tank cars of the relatively low pressuretype for the transmission of liquifled gases. V v

.In the past liquified or highly compressed gases have been transportedin comparatively small containers of extremely heavy, constructioncapable of withstanding the extreme pressure of the gas regardless ofthe outside or atmospheric temperature. In certain rare instances largecontainers for transport of liquiiled gases or highly compressed gasesunder the same conditions have been built but such con-. tainers inorder to comply with I. C. C. regulations must be forged from a singlebillet. These large containers are manufacture and of enormous weight,in most instances having steel walls two to three inches thick but insome cases the walls are live to six inches in-thickness. It has alsobeen proposed tures whose cost may be but a fraction of the cost of theforged structures, but all of these insulated structures heretoforebuilt have required an excessive wastage of lading in order to maintainthe lading at the necessary low temperature to prevent bursting of thecontainer shell. It is an object, therefore, of the present invention toprovide a wholly insulated tank car in which liquified gases may betransported for comparatively long periods of time without any loss oflading and with a very slight increase in temperature, in other words,with a minimum loss of energy.

A further object of the invention is the provision of a wholly insulatedtank car of the medium pressure type complying fully with I. C. C.regulations and in which all metallic paths for heat loss from the tankshell are reduced to a minimum with the paths of small cross section andgreat length.

Another object of the invention is the provision of a wholly insulatedtank car with a iully insulated dome-like structure protecting allnozzle fittings against heat losses.

These and other objects of the invention will be apparent to personsskilled in the art from a study of the following description andaccompanying drawing, in which Figure l is a longitudinal centralsectional view taken through the nozzle and dome-like structure; 7

Fig. 2 is a'plan view of the domealike structure with parts thereofbroken away to better disclose the interior construction, and

10 wardly from shown in Figure 1. This nozzle or opening terablyfastened in place.

Fig. 3 is a diagrammatic view of the complete tank car having theimproved construction.

Referring now to the drawing in detail, it will be seen that the tank Ais supported upon trucks B of the customary type and that the tank hasformed thereon a dome-like structure C. The tank itself is formed. asclearly shown in Figure 1, of a comparatively heavy shell 2 completelyclosed except for a nozzle 4, which projects upthe shell of the tank asclearly minates in laterally projecting flanges 6 drilled and tapped toreceive stud bolts 8, by means of which a nozzle cover or lid in may beremov- This cover or lid is provided with a projecting rib l2 adapted tofit in a machined groove M formed in the nozzle flange, thus forming atight joint and preventing any leakage of pressure from'the tankinterior. The

lid or cover is drilled and tapped to receive into transport liquifiedgases in insulated strucduction and eduction pipes I6 and I8.respectively and above which are securely fastened inlet and outletvalves 20 and 22 respectively. The exterior connection to these valvesis made through i 25 pipes 24 extending upwardly parallel to the valvestem in spaced relation thereto and terminating in a dischargeconnection normally capped by a plate or other means 26. In this mannera ready connection for charging or discharging the tank -0 may be madeand any leakage past the valve seat becomes impossible when the cap isin place. The cover or lid also isprovided with any suitable number ofopenings 28 in which safety valves may be inserted. In the presentinstance there are three of these openings and three safety valvesindicated at 30, 32 and 34 respectively. These valves are ofsubstantially identical con-/ struction and are set to open at variouspressures. For example, valve 30 may be set to open at 300 pounds persquare inch, valve 32 at 340 pounds pressure and valve 34 at 3'i5 poundspressure. In addition to these valves and as an added safety feature anapproved safety vent 36 is provided and is of the type having afrangible disc designed to rupture at not more than 450 pounds pressure,thus positively protecting the tank shell against rupture. The formofthe safety valves is immaterial but they are preferably of the typeshown and which are fully disclosed in Willoughby Patent 1,774,690. Inorder to direct the escaping gases from the safety valves shortvertically extending pipes 38 are provided secured to the valvestructure and extending upwardly a sufficient distance as to directmediate its length with an inner [with the other leg disposed insidewith the lower edge supported by means of a top ring structure 62 of theescaping gases upwardly and away from the charging and dischargingvalves. In order to protect the various valve structures ascomparatively heavy open ended cylinder 40 is provided, having its loweredge welded or otherwise secured to the nozzle lid or cover andremovable therewith. This cylindrical protecting member is of sufficientheight as to project slightly above the various valve structures. Theentire tank shell 2 is covered by means of insulation 42 which, in thepresent case, com-" prises cork of inch thickness. This insulation isprotected against entrance of moisture and destruction by means of aprotecting steel housing 44 completely encasing the tank insulationexcept for a small area adjacent the nozzle. The opening in the outershell adjacent the nozzle has attached thereto, as by spot welding orsimilar means, an angle shaped structure 46 having an upstanding flange48 to which is in turn attached a second angular structure having oneleg parallel to leg 48 and secured thereto, while the other leg 50 isdirected outwardly substantially parallel to the protective casing ofthe tank, thus in efiect a ledge and upstanding flange is providedextending completely around the opening in the outer protective casing.

In order to fully insulate thetank nozzle cover or lid together with itsvalve structures, an inner cylindrical casing 52 is provided havingattached thereto at its lower edge an angle form member 54 adapted torest lightly on the tank insulation. This cylindrical inner casing isprovided inter- 2 form ring 56 the casing and of the protective cylinder40, with the web of the Z shaped ring resting upon the upper edge of theprotective housing and supporting the protective inner casing 52. Theinner casing forms a base around which cork or similar insulation 60 maybe fitted angle struc tank. This protected by substantially invertedchannel form attached to an outer casing 64, having its lower edgeterminating inan outwardly directed flange 66 adapted to rest upon andbe bolted as at 68 to the flange 50 of the tank protective structure,thus it will be seen that by removal of the bolts or other securingmeans 68 the. entire protective dome like structure may be lifted off ofthe tank without disturbing the insulation.

In order to close the upper end of the dome like insulating housing, alid 10 is provided formed on a top plate 12, bottom plate 14 and ringlike connected channel form side structure 16, thus inclosing a spacewhich may be filled with insulation 78. As clearly shown, the top plateof the lid overlaps the upper member 62 of the housing and metalliccontact between the lid and housing is broken by means of an insulatinggasket 80 which also will prevent any leakage oi. air or gas from thehousing. The lid may be directly removable or, as in the present case,it may behinged as at 82 to the dome like housing and secured in placeby locking and sealing means 84. Since the insulated dome like structureis substantially air tight, it is necessary to vent the same and this isaccomplished by means of a high level vent V formed by a pipe 86extending through the lid and capped by means of a screen 88 and ametallic cap 90, all of which will prevent entrance of moisture orforeign having one leg rigidly secured to ture 54 and by the insulationof the insulation is completely housed and matter into the interior ofthe insulated dome like structure while permitting escape of gasesliberated by the safety valves. It will be seen that the only directmetallic path for conducting heat from the tank structure to the outsideair is established by cylindrical casing 40, ring 56 and the upper partof inner casing 52. This path, oi course, can be broken if desired bymeans of a gasket inserted between ring 56 and the upper edge ofcylindrical housing 40 but the use of such a gasket is not deemednecessary since the entire cavity in which the valves are located willbe at an extremely low temperature. Additional metallic paths formed bythe vent pipe and by the sides of the lid are also established betweenthe cavity to the dome like structure and the atmosphere but these pathsare of small cross section and comparatively great length and can onlytransmit heat from the atmosphere to the cavity and not to the tankshell and the rate of transfer will be extremely slow since in manyinstances, such as with CO2 gas, the cavity may be considered as filledwith a fairly good insulator. It has been found that six inches of cork,or equivalent insulation, is suflicient to economically insulate thedome like structure.

It is believed from the preceding description that the advantages of theconstruction will be apparent, but these advantages may be bettenrealized from a study of the following: A tank car constructed with teninches of cork insulation and with the steel nozzle cover and valvefittings exposed when loaded with 60,000 pounds of carbon dioxide at0.F. and with an outside temperature of will transmit through the cork2148 B. t. u.s per hour and through the tank anchors 1260 B. t. u.s perhour, making a total through the cork and anchors of 3408 B. t. u.s perhour. The losses through the steel nozzle cover and valve fittings witha 20 inch diameter cover amounts to 30,485 B. t. u.s per hour, giving atotal loss for the entire tank of 33,893 B. t. u.s with a hundred degreetemperafrom developing an excessive pressure, its tem- I perature shouldnot exceed 2 F. and to maintain this low temperature would require theescape of 282 pounds of liquid CO2 per hour and, further, this losswould begin in 3 hours and 40 minutes after the lading was placed in thetank at 0 F.

When, however, the nozzle and valve fittings are insulated as shown anddescribed the total lossesthrough the insulated dome assembly are only287 B. t. u.s per hour. In other words, a saving of over 30,000 B. t.u.s per hour has been made and the losses through the insulated domelike structure are only approximately one-ninth of the total loss of thetank which is now 3695 B. t. u.s per hour. To offset this loss andprevent temperature raise beyond 2 F. would require only 30 and 1 5pounds of liquid C02 per with 60,000 pounds of liquid at 0 F. previouslypointed out, the safety set to operate at 301 pounds pressure, which isthe pressure at which liquefied CO2 at 2 F. must be retained.

By comparison it will be seen that a very great saving is accomplishedthrough the proper insulation of the nozzle and valve fittings and thatwith the structure shown and described it will ing secured to and adome-like lid, control. valves and in many cases be possible to transmitliquefied CO2 in the neighborhood of a without any loss of liquid gaswhatsoever occurring, in other words, of the lading has risen 2 F. Itwill likewise be seen that there is approximately 30 hours difierence intime between a wholly insulated and a partially insulated tank beiorelosses occur and these thirty hours would represent the loss of nearlytwo tons of liquid or, in other words, onefifteenth of the lading fromthe partially insulated tank.

While the invention or less in detail and has been described more withparticular emphasis on the transportation of liquid CO2, it'will beobvious to persons skilled in the art that various modifications andrearrangements may be made and that the construction is equallyapplicable to transportation of liquids or gasesother than CO: and all.modifications and rearrangements of parts and as will fall within thescope of the appended claims which define my invention; a

What is claimed is: 1. In a railway c'ar tank for the low temperaturetransportation of liquid lading under pressure, a pressure retainingbody, body insulation covering. the body, nozzle means carried by saidbody and projecting through said body insulation, a cover plate for saidnozzle, control valves for the liquid lading carried by said coverplate, and an insulated dome-like structure completely covering saidcontrol valves and nozzleand substantially preventing heat lossestherefrom, said dome-like structure being supported at least in partupon said cover plate by relatively thin metal means. t a

2. In a railway car tank for the low temperature transportation orliquid lading under pressure, a pressure retaining body, body insulationbody, nozzle means carried by said body and projecting through said bodyinsulation, protective means covering said insulation and terminating inspaced relation to said nozzle insulated dome-like structure secured tosaid protective means and completely housing said nozzle means tothereby substantially prevent heat losses therefrom, said dome likestructure. being supported, at least upon the nozzle structure but freeof connection thereto whereby movements of the protective housing willnot be transmitted tothc nozzle structure.

3. In a railway car tank for the low temperature transportation ofliquid lading under pres sure, a pressure retaining body having a nozzleprojecting outwardly therefrom, body insulation coverin the entire bodyto a depth substantially equal to the nozzle projection, a lid securedto said nozzle; control valves for the liquid ladthe lid, protectivemeans secured to said lid and extending upwardly therefrom, structuresupported on said and completely housing-sald protective means, saidfully insulated to :prevent loss of heat from the control valves andlid.

protective meansthousand miles before the temperature said nozzle,control valves uses of the structure are contemplated a vent heat loss4. In a railway car tank for the low temperature transportation orliquid lading under pres sure, a pressure retaining body having a nozzleprojecting outwardly covering the entire body to a depth substantiallyequal to the nozzle projection, a lid secured to for the liquid ladingsecured to the lid, protective casing secured to said lid and extendingupwardly therefrom, and a dome-like structure supported on saidprotective casing and completely housing said lid, control valves andprotective casing, said dome-like structure being fully insulated toprevent loss of heat from the control valves and lid, and said dome-likestructure being formed with a hinged cover permitting access to thecontrol valves.

5. In a railway car tank for the low temperature transportation ofliquid lading under pressure, a pressure retaining body, body insulationcovering the body, nozzle means carried by said body and projectingthrough said body insulation, and. a dome-like structure completelycovering said nozzle means to substantially pre-' therefrom, saidstructure comprisin'gan inner casing supported on said nozzle structurein spaced relation thereto, insulation covering said inner casing, anouter casing connected to said inner casing and protecting saidinsulation, and a movable insulated lid carried by said casings. a

6. In a railway tank car including a body, I insulation covering saidbody, a nozzle carried by said body and extending through saidinsulation, a cover plate for sealing said nozzle, control valvescarried by said cover plate, a protective casing enclosing said controlvalves and carried by said cover plate, an insulated covering enclosingsaid casing and spaced therefrom, said insulated covering beingsupported in direct contact with the insulation of said car body, and aclosure forsaid insulated covering adapted in its closed position tooverlie said protective casing in substantially axial alignment.

7. In a railway tank car including a tank body having an insulatedcovering, a nozzle extending from said body through said covering, acover plate for said nozzle, control valves carried by said cover plate,a protective casing fixed to the marginal edge or said cover said.control valves, an insulated cover including a closure member enclosingsaid protective casing, said insulated cover forming a unit remov ablyconnected to the car body structure, and said closure member beingadapted to immediately overlie said protective casing.

8. In a railway tank car ing an insulated for sealing said nozzle,control valves carried by said plate, a wall member fixed to the plateand extending about said control valves, and a domelike structure formedof relatively thick insulating material and including a removable tionarranged about said wall member and being detachably connected to thecar therefrom, body insulation plate and enclosing including a bodyhavcovering and a nozzle. a plate wall por-v 1 CLYDE H. FOL-MSBEE.

